Note 4 - Loans Held for Investment - Past Due Loans (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Loans past due	$ 4,211,000	$ 5,734,000
Loans current	697,232,000	602,131,000
Credit exposure by assigned risk grade	701,443,000	607,865,000
Loans over 90 days past due, still accruing		115,000
Residential Portfolio Segment [Member]
Credit exposure by assigned risk grade	75,293,000	72,320,000
Residential Portfolio Segment [Member] | Real Estate Loan [Member]
Loans past due	1,789,000	2,699,000
Loans current	65,475,000	65,530,000
Credit exposure by assigned risk grade	67,264,000	68,229,000
Loans over 90 days past due, still accruing		115,000
Residential Portfolio Segment [Member] | Construction Loans [Member]
Loans past due		120,000
Loans current	7,875,000	3,814,000
Credit exposure by assigned risk grade	7,875,000	3,934,000
Loans over 90 days past due, still accruing
Residential Portfolio Segment [Member] | Lots and Raw Land [Member]
Loans past due
Loans current	154,000	157,000
Credit exposure by assigned risk grade	154,000	157,000
Loans over 90 days past due, still accruing
Residential Portfolio Segment [Member] | Lease Receivables [Member]
Credit exposure by assigned risk grade	21,236,000	17,235,000
Commercial Portfolio Segment [Member]
Credit exposure by assigned risk grade	556,941,000	472,688,000
Commercial Portfolio Segment [Member] | Real Estate Loan [Member]
Loans past due	1,752,000	1,384,000
Loans current	376,421,000	337,330,000
Credit exposure by assigned risk grade	378,173,000	338,714,000
Loans over 90 days past due, still accruing
Commercial Portfolio Segment [Member] | Construction Loans [Member]
Loans past due
Loans current	56,118,000	42,987,000
Credit exposure by assigned risk grade	56,118,000	42,987,000
Loans over 90 days past due, still accruing
Commercial Portfolio Segment [Member] | Lots and Raw Land [Member]
Loans past due		69,000
Loans current	33,434,000	28,202,000
Credit exposure by assigned risk grade	33,434,000	28,271,000
Loans over 90 days past due, still accruing
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans past due	72,000	3,000
Loans current	67,908,000	45,478,000
Credit exposure by assigned risk grade	67,980,000	45,481,000
Loans over 90 days past due, still accruing
Commercial Portfolio Segment [Member] | Lease Receivables [Member]
Loans past due		95,000
Loans current	21,236,000	17,140,000
Credit exposure by assigned risk grade	21,236,000	17,235,000
Loans over 90 days past due, still accruing
Consumer Portfolio Segment [Member]
Credit exposure by assigned risk grade	69,209,000	62,857,000
Consumer Portfolio Segment [Member] | Real Estate Loan [Member]
Loans past due	248,000	779,000
Loans current	16,719,000	16,460,000
Credit exposure by assigned risk grade	16,967,000	17,239,000
Loans over 90 days past due, still accruing
Consumer Portfolio Segment [Member] | Construction Loans [Member]
Loans past due
Loans current	105,000	196,000
Credit exposure by assigned risk grade	105,000	196,000
Loans over 90 days past due, still accruing
Consumer Portfolio Segment [Member] | Lots and Raw Land [Member]
Loans past due	89,000	351,000
Loans current	8,886,000	9,292,000
Credit exposure by assigned risk grade	8,975,000	9,643,000
Loans over 90 days past due, still accruing
Consumer Portfolio Segment [Member] | Lease Receivables [Member]
Credit exposure by assigned risk grade	8,975,000	9,643,000
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	252,000	228,000
Loans current	36,563,000	29,481,000
Credit exposure by assigned risk grade	36,815,000	29,709,000
Loans over 90 days past due, still accruing
Consumer Portfolio Segment [Member] | Other Loans [Member]
Loans past due	9,000	6,000
Loans current	6,338,000	6,064,000
Credit exposure by assigned risk grade	6,347,000	6,070,000
Loans over 90 days past due, still accruing
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans past due	1,902,000	4,249,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member]
Loans past due	1,048,000	2,238,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member] | Construction Loans [Member]
Loans past due		120,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member] | Lots and Raw Land [Member]
Loans past due
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member]
Loans past due	726,000	1,054,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Construction Loans [Member]
Loans past due
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Lots and Raw Land [Member]
Loans past due		69,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans past due		3,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Lease Receivables [Member]
Loans past due
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Real Estate Loan [Member]
Loans past due		429,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Construction Loans [Member]
Loans past due
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Lots and Raw Land [Member]
Loans past due		211,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	121,000	122,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Other Loans [Member]
Loans past due	7,000	3,000
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans past due	265,000	521,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member]
Loans past due	176,000	107,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member] | Construction Loans [Member]
Loans past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member] | Lots and Raw Land [Member]
Loans past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member]
Loans past due	4,000	227,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Construction Loans [Member]
Loans past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Lots and Raw Land [Member]
Loans past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Lease Receivables [Member]
Loans past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Real Estate Loan [Member]
Loans past due	42,000	113,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Construction Loans [Member]
Loans past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Lots and Raw Land [Member]
Loans past due	8,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	33,000	72,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Other Loans [Member]
Loans past due	2,000	2,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans past due	2,044,000	964,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member]
Loans past due	565,000	354,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member] | Construction Loans [Member]
Loans past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member] | Lots and Raw Land [Member]
Loans past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member]
Loans past due	1,022,000	103,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Construction Loans [Member]
Loans past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Lots and Raw Land [Member]
Loans past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans past due	72,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Lease Receivables [Member]
Loans past due		95,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Real Estate Loan [Member]
Loans past due	206,000	237,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Construction Loans [Member]
Loans past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Lots and Raw Land [Member]
Loans past due	81,000	140,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	98,000	34,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Other Loans [Member]
Loans past due		$ 1,000